A main structure of the thin film transistor liquid crystal display (TFT-LCD) has an LCD panel and a back light. The LCD panel has an array structure, a color substrate, and a liquid crystal cell disposed therebetween. With the rapid development of liquid crystal display technology, existing three-color RGB technical cannot meet the current customer demand. Recently, customers pay more attention to four-color RGBW technology with a high transmittance, a high brightness, and a low energy consumption.
During a production process of the display, the liquid crystal cell needs to be lighting detection before the LCD light panels bind to ICs to prevent bad products from entering into the next step. The array structure disposes signal lines corresponding to monochrome data lines. When the liquid crystal cell is tested (cell test), detection signals are inputted in pins corresponding to each signal line, signal lines with same detection signals are shorted connected with a shorting bar.
Refer to FIG. 1, a detection unit of three-color RGB technical displays has three shorting bars (R/G/B) 111, 112, 113 connecting to three pixel signal lines 131, 132, 133 respectively through three pixel pins 121, 122, 123. A cell test step is processed for lighting white/solid red/solid green/solid blue screen to detect the screen quality. Similarly, refer to FIG. 2, a detection unit of four-color RGBW displays has four shorting bars (R/G/B/W) 211, 212, 213, 214 connecting to four pixel signal lines 231, 232, 233, 234 respectively through four pixel pins 221, 222, 223, 224. A cell test step is processed for lighting white/solid red/solid green/solid blue/solid white screen to detect the screen quality.
Four-color RGBW displays are an improved technology over three-color RGB displays. In the process of improving products, manufacturers use existing equipment and processes for reducing the cost. Therefore, in the process of four-color RGBW displays, manufacturers want to reduce components, such as array masks, in the changing design. If the array masks of four-color RGBW displays and those of three-color RGB displays are the same, manufacturers need to prepare a mold for manufacturing the array mask.
However, refer to FIG. 3, in the process of improving three-color RGB displays to four-color RGBW, the array masks could not be changed, the connection of the shorting bars and pins are same as three-color RGB displays (shown FIG. 1), the number of pixel signal lines are changed to four from three, each shorting bar has a white pixel. In the cell test step, which can light a solid white screen, and cannot light a solid color screen. Therefore, the array masks need to be changed, and designers only reduce to change the array mask. If the design of three-color RGB displays with three shorting bars (R/G/B) in FIG. 1 is changed to the design of four-color RGBW displays with four shorting bars (R/G/B/W) in FIG. 2, which need to change 2 or more array masks. Moreover, the array mask of three-color RGB displays does not have enough space to increase the number of the bars on the board, which need to change a new array mask. The array mask is changed more, and the production cost is increased for manufacturers. Therefore, the technical field of four-color RGBW displays need a new design, which can light a solid white screen in the cell test step base on reducing the changes to the array masks.